The present invention relates to artificial spinal discs, and instruments and methods associated with the implantation of such artificial spinal discs.
Current spinal therapies for treating problematic spinal discs are moving from rigid fixation of adjacent vertebrae across the problematic disc space, such as with rods or plates, to maintaining the relative motion of the adjacent vertebrae, such as with artificial spinal discs. For instance, an artificial spinal disc may be utilized to treat degenerative disc disease, including a herniated nucleus pulposus and/or posterior osteophytes, which causes radiculopathy and/or myelopathy. Radiculopathy is compression of a spinal nerve root, while myelopathy is compression of the spinal cord. Both are conditions that may result in an individual experiencing pain or tingling in the arms, legs, back and/or neck.
Current artificial spinal discs have drawbacks relating to their fixation to the adjacent vertebrae and their ability to be revised, or removed, after their implantation. For instance, current artificial discs may have special contours that need to be machined into the endplates of the adjacent vertebrae. Further, current artificial discs may require special machining of the vertebrae and/or implantation instrumentation to accommodate spikes, fins, or other structures extending into the adjacent vertebrae that are used to fixate the disc to the vertebrae. Additionally, current artificial discs may include bone in-growth surfaces across the entire vertebrae-contacting surface. This makes it difficult to remove the artificial disc, as is sometimes required, once the artificial disc is implanted.
Similarly, the associated implantation instruments and methods have a number of drawbacks relating to their complexity or to their suitability for use in more sensitive areas of the spine, such as in the cervical spine. For instance, some implantation systems require the use of many different instruments and devices to prepare the disc space and properly insert the artificial disc. Further, some implantation systems rely on impacting, or hammering, features into the bone to accommodate the artificial disc. Such impaction techniques may be suitable in certain areas of the spine, like in the lumbar spine, but are not as desirable in other areas of the spine, like the cervical spine, where the proximity of the spinal cord and nerve roots would favor more delicate procedures.